Solutions to the system in Example IS are given as

Solutions to the system in Example IS are given as

(x₁, x₂, x₃, x₄) = (−1 − 2a + 3b, 4 + a − 2b, a, b)

Evaluate the three equations of the original system with these expressions in a and b and verify that each equation is true, no matter what values are chosen for a and b.